1. Field of the Invention
The present invention relates to a generally four-sided filament having a central axial four-sided void useful as a carpet yarn able simultaneously to impart both good color strength and relatively high xe2x80x9cglitterxe2x80x9d to a carpet made therefrom, and, to a spinneret plate for producing the filament.
2. Description of the Prior Art
xe2x80x9cGlitterxe2x80x9d, when describing a filament used to form a carpet yarn, is a characteristic of the luster of the yarn and refers to the shiny appearance of the yarn when light is reflected by the filaments. A yarn having high glitter is also synonymously described in the art as having a xe2x80x9cmetallicxe2x80x9d luster or a high degree of xe2x80x9csparklexe2x80x9d.
Carpet yarns having levels of glitter higher than those used in the past have become fashionable. U.S. Pat. No. 6,048,615 (Lin, RD-7395) assigned to the assignee of the present invention, discloses a trilobial filament formed from a thermoplastic synthetic polymer material, which exhibits high glitter, excellent durability, and good soiling resistance.
It is also desirable in some instances that the carpet yarn imparts good color strength in addition to imparting a high glitter. Color strength is a measure of the depth of color richness of a carpet.
In view of the foregoing, it is believed advantageous to provide a yarn useful as a carpet yarn that exhibits a relatively high glitter, yet at the same time has a good color strength.
In one aspect the present invention is directed to a thermoplastic synthetic polymer filament which, due to its combination of good color strength and high glitter, is believed to be especially useful as carpet yarn. The filament of the present invention has a four-sided exterior configuration with an exterior modification ratio in the range from about 1.15 to about 2.0. The filament has a four-sided void extending centrally and axially therethrough. Each apex of the four-sided void extends toward the approximate midpoint of one respective side of the exterior configuration of the filament. The four-sided void has a modification ratio in the range from about 1.2 to about 2.0 and occupies from about five percent (5%) to about thirty percent (30%) of the cross sectional area of the filament.
In another aspect the present invention is directed to a spinneret plate for producing the thermoplastic synthetic polymer filament as above described. The spinneret plate has a cluster of four orifices centered about a central point. Each orifice includes a generally isosceles-triangle-shaped major portion from which extends a pair of legs, each leg of one orifice being spaced from the leg of an adjacent orifice to define a gap therebetween.